Systems and methods for cobalt recovery

ABSTRACT

Various embodiments provide a method comprising leaching a cobalt bearing material to form a slurry, filtering the slurry to yield solids and a cobalt bearing liquid phase, performing a solution extraction of the cobalt bearing liquid phase to yield a purified cobalt bearing liquid phase, precipitating cobalt gypsum by adding lime to a first portion of the purified cobalt bearing liquid phase, and recycling the cobalt gypsum to the leaching.

FIELD OF INVENTION

The present invention relates, generally, to systems and methods forrecovering metal values from metal-bearing materials, and morespecifically, to systems and methods for recovering cobalt and othermetal values.

BACKGROUND OF THE INVENTION

Cobalt is an industrially important element that may be used in variouscatalysts, dyes, alloys, inks, battery additives, and other industriallybeneficial products. Cobalt may be found in nature in a variety of formsand in a variety of ores. Cobalt containing ores include cobaltite,heterogenite (CoOOH), erythrite, glaucodot, and skutterudite. As foundin nature, cobalt often exists in an oxidation state other than zero.For example, cobalt is often found in the form of cobalt II and cobaltIII.

In conventional processes, cobalt containing materials precipitated withmagnesium oxide and subsequently leached are often difficult to filterduring metal recovery. In addition, large volumes of aqueous solutionare typically employed. More efficient systems and methods for cobaltrecovery would be commercially and industrially advantageous.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides systems and methods formetal value recovery, such as cobalt recovery. In various embodiments, amethod is provided comprising leaching a cobalt bearing material to forma slurry, filtering the slurry to yield solids and a cobalt bearingliquid phase, performing a solution extraction of the cobalt bearingliquid phase to yield a purified cobalt bearing liquid phase,precipitating cobalt gypsum by adding lime to a first portion of thepurified cobalt bearing liquid phase, and recycling the cobalt gypsum tothe leaching.

Further areas of applicability will become apparent from the detaileddescription provided herein. It should be understood that thedescription and specific examples are intended for purposes ofillustration only and are not intended to limit the scope of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the present invention is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present invention, however, may bestbe obtained by referring to the detailed description and claims whenconsidered in connection with the drawing figures, wherein like numeralsdenote like elements and wherein:

FIG. 1 is a flow diagram illustrating an exemplary process in accordancewith various embodiments of the present invention;

FIG. 2 is a flow diagram illustrating an exemplary process, including aleaching process, in accordance with various embodiments of the presentinvention;

FIG. 3 is a flow diagram illustrating an exemplary process, including anupstream bleed, in accordance with various embodiments of the presentinvention;

FIG. 4 is a flow diagram illustrating an exemplary process, including asource of the cobalt bearing material, in accordance with variousembodiments of the present invention;

FIG. 5 is a flow diagram illustrating an exemplary process, includingmultiple sources of the cobalt bearing material, in accordance withvarious embodiments of the present invention; and

FIG. 6 is a flow diagram illustrating an exemplary process in accordancewith various embodiments of the present invention.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present invention, its applications, or its uses.It should be understood that throughout the drawings, correspondingreference numerals indicate like or corresponding parts and features.The description of specific examples indicated in various embodiments ofthe present invention are intended for purposes of illustration only andare not intended to limit the scope of the invention disclosed herein.Moreover, recitation of multiple embodiments having stated features isnot intended to exclude other embodiments having additional features orother embodiments incorporating different combinations of the statedfeatures.

Furthermore, the detailed description of various embodiments hereinmakes reference to the accompanying drawing figures, which show variousembodiments by way of illustration. While the embodiments are describedin sufficient detail to enable those skilled in the art to practice theinvention, it should be understood that other embodiments may berealized and that logical and mechanical changes may be made withoutdeparting from the spirit and scope of the present invention. Thus, thedetailed description herein is presented for purposes of illustrationonly and not of limitation. For example, steps or functions recited indescriptions any method, system, or process, may be executed in anyorder and are not limited to the order presented. Moreover, any of thestep or funictions thereof may be outsourced to or performed by one ormore third parties. Furthermore, any reference to singular includesplural embodiments, and any reference to more than one component mayinclude a singular embodiment.

The present invention relates, generally, to systems and methods forrecovering metal values from metal-bearing materials, and morespecifically, to systems and methods for recovering cobalt. Variousembodiments of the present invention provide a process for recoveringcobalt using, among other things, a precipitation and filtrationprocess. These improved systems and methods disclosed herein achieve anadvancement in the art by improving filtration, reducing acid volumesconsumed, and improving recovery yields.

In particular, it has been discovered that a precipitation andfiltration process, such as one using gypsum (e.g., calcium sulfate orCaSO₄), tends to, in various embodiments, improve filtration of cobaltbearing materials, increase cobalt recovery yield, and/or allow for anupstream bleed that reduces solution volumes in other processes.

In conventional processes, cobalt containing materials precipitated withmagnesium oxide (MgO) and subsequently leached tend to be difficult tofilter. It has been found that gypsum added via lime as a precipitant inone of the process stages tends to act as a filtering aid without suchnegative effects.

In conventional systems, large volumes of liquor having low cobaltconcentrations are processed in various metallurgical processes, such asion exchanges and solution extraction. Typically, these processes end inan electrowinning process that produces cobalt metal. However, it hasbeen found that by placing a bleed after a filtration process, acidvolumes used in downstream processes may be reduced. Thus, metalrecovery processes may act on higher cobalt concentration liquors thanin previous systems. Accordingly, cobalt recovery efficiency isenhanced, as well as reagent costs lessened.

While various embodiments of the present invention may be constructedand/or operated in any physical location, it is advantageous to operatevarious embodiments in close proximity to a primary metal leachingprocess. A primary leaching process may comprise a leaching process thatis intended to liberate one or more metals from a metal bearingmaterial. For example, in various embodiments, a primary leachingprocess comprises a leaching process to liberate copper and cobalt froma metal bearing material that comprises copper and cobalt. By operatingin close proximity to a primary metal leaching operation, certainoutputs of various embodiments may be forwarded to the primary leachingprocess. This allows metal content to be retained and further processed,decreasing net loss of metal, for example, by reducing the amount ofmetal sent to tails or residue.

With reference to FIG. 1, a metal recovery process 100 is illustratedaccording to various embodiments of the present invention. Metalrecovery process 100 comprises subjecting cobalt bearing material (“CoMAT”) 102 to reactive process 104, filtration 106, and conditioning 108.A first portion of the output of conditioning 108 is sent toprecipitation and filtration 112 and a second portion of the output ofconditioning 108 is sent to further processing 110.

Cobalt bearing material 102 may be an ore (cobaltite, heterogenite(CoOOH), erythrite, glaucodot, skutterudite, other cobalt containingores, and mixtures of cobalt containing ores with ores bearing othermetal values), a concentrate, a process residue, an impure metal salt, apreprocessed cobalt bearing material, combinations thereof, or any othermaterial from which cobalt values are present. Cobalt, whether in metalor ionic form, may be recovered from cobalt bearing material 102 inaccordance with various embodiments of the present invention. Variousaspects and embodiments of the present invention, however, proveespecially advantageous in connection with the recovery of cobalt from apreprocessed cobalt bearing material. A preprocessed cobalt bearingmaterial may comprise a material that has been subjected to a priormetallurgical process. For example, a metallurgical process may resultin the formation of cobalt hydroxide (Co(OH)₂). Cobalt hydroxide may beformed by combining a cobalt bearing material with magnesium oxide (MgO)and/or lime. It should be appreciated that a preprocessed cobalt bearingmaterial may contain various other constituents as impurities orcoprecipitates, such as copper, zinc, manganese and/or nickel. Invarious embodiments, cobalt bearing material 102 comprises cobalthydroxide. In various embodiments, cobalt bearing material 102 comprisescobalt hydroxide produced by addition of magnesium oxide to a materialcontaining cobalt ions. In various embodiments, cobalt bearing material102 comprises cobalt hydroxide produced by addition of lime to amaterial containing cobalt ions. In various embodiments, cobalt bearingmaterial 102 comprises cobalt hydroxide produced by addition of limeand/or magnesium oxide. Cobalt produced using magnesium oxide isgenerally considered of greater quality than cobalt produced using lime,though various factors, including reagent costs, may affect theselection of an appropriate cobalt bearing material.

With continued reference to FIG. 1, after cobalt bearing material 102has been suitably prepared, cobalt bearing material 102 may be subjectedto reactive process 104 to put cobalt in cobalt bearing material 102 ina condition for later cobalt recovery steps. For example, exemplarysuitable processes include reactive processes that tend to liberate thecobalt from cobalt bearing material 102. In accordance with variousembodiments, reactive process 104 may comprise leaching.

Leaching may be any method, process, or system that enables cobalt to beleached from cobalt bearing material 102. Typically, leaching utilizesacid to leach cobalt from cobalt bearing material 102. SO₂ and/or othersuitable reducing agent may be added to reduce Co(III) to Co(II), asCo(II) is then readily soluble in the leach liquor. Basic (i.e.,caustic) leaches may be used, however. For example, leaching can employa leaching apparatus such as for example, a heap leach, a vat leach, atank leach, a simultaneous grind-leach apparatus, a pad leach, a leachvessel or any other leaching technology, known to those skilled in theart or hereafter developed, that is useful for leaching cobalt fromcobalt bearing material 102.

In accordance with various embodiments, leaching may be conducted at anysuitable pressure, temperature, and/or oxygen content. Leaching canemploy one of a high temperature, a medium temperature, or a lowtemperature, combined with one of high pressure, or atmosphericpressure. Leaching may utilize conventional atmospheric or pressureleaching, for example, but not limited to, low, medium or hightemperature pressure leaching. As used herein, the term “pressureleaching” refers to cobalt recovery process in which material iscontacted with an acidic or a basic solution and oxygen under conditionsof elevated temperature and pressure. Medium or high temperaturepressure leaching processes which are generally thought of as thoseprocesses operating under acidic conditions at temperatures from about120° C. to about 190° C. or up to about 250° C.

In accordance with various embodiments, reactive processing step 104 maycomprise any type of reactive process that is capable of yielding cobaltin cobalt bearing material 102 in a condition to be subjected to latermetal recovery steps. In various embodiments, reactive processing 104yields cobalt bearing reactive processed material 105, described indetail herein below.

Reactive processed material 105 may be directed to filtration 106.Filtration 106 may comprise any suitable filtration process. Forexample, vacuum filters such as a belt filter or disc filter may beused. In addition, pressure filters such as a plate and frame filter maybe used.

Filtration 106 may separate the cobalt bearing reactive processedmaterial 105 into a solid phase and a liquid phase. The solid phase maybe treated as residue. However, in various embodiments, the solid phaseis sent to a primary leaching process. A primary leaching process maycomprise a leaching process that is intended to liberate one or moremetals from a metal bearing material. For example, in variousembodiments, a primary leaching process comprises a leaching process toliberate copper and cobalt from a metal bearing material that comprisescopper and cobalt. The liquid phase of reactive processed material 105comprises filtrate 107. Filtrate 107 is forwarded to conditioning 108.

In various embodiments, conditioning 108 may be for example, but is notlimited to, a solid liquid phase separation step, an additional leachstep, a pH adjustment step, a dilution step, a solution extraction step,a concentration step, an ion exchange step, a metal precipitation step,a filtering step, a settling step, and the like, as well as combinationsthereof. In various embodiments, conditioning 108 may comprise asolution extraction separation step configured to selectively extractimpurities from, as described in further detail herein.

In various embodiments, conditioning 108 produces conditioned solution118 and conditioned solution 116. Conditioned solution 118 may beforwarded to precipitation and filtration 112, to precipitate any cobaltthat was stripped from the organic phase in the wash/scrub stage.

Precipitation and filtration 112 may comprises a filtration processwherein a reagent is added to selectively precipitate cobalt.Precipitation and filtration 112 may comprise a precipitation thatincludes the use of a variety of precipitants, including, for example,calcium, lime (calcium hydroxide and/or calcium oxide), calciumcarbonate and milk of lime (certain preparations of calcium hydroxide).In various embodiments, any suitable source of gypsum or lime may beused in precipitation and filtration 112. For example, lime may be addedto precipitation and filtration 112 to precipitate cobalt as cobaltgypsum (“CoGyp”). Precipitation and filtration 112 thus producesprecipitated cobalt 114. Precipitated cobalt 114 may be passed toreactive process 104.

Conditioned solution 116 may be passed to further processing 110.Further processing 110 may comprise any metal recovery process, such asion exchange, electrowinning, solution extraction, carbon columnfiltering, and combinations thereof.

With reference to FIG. 2, metal recovery process 200 is illustrated.Metal recovery process 200 contains certain steps found in metalrecovery process 100, but FIG. 2 illustrates an embodiment whereinreactive process 104 comprises leach 202 and wherein conditioning 108(as illustrated in FIG. 1) comprises solution extraction 204.

Leach 202 comprises a leach process that is intended to liberate cobaltfrom CoMAT 102. Leach 202 comprises leaching CoMAT in the presence ofacid and, in various embodiments, gypsum. The acid used in leach 202 maycomprise, for example, sulfuric acid and/or hydrochloric acid. Leach 202may be performed in a heap or a tank or other vessel. Leach 202 may beperformed at temperatures above ambient temperatures, as furtherdescribed herein. In various embodiments, additional reagents are addedto leach 202. For example, sulfur dioxide may be introduced in leach202. Sulfur dioxide addition acts to reduce cobalt III into cobalt II,which is more easily dissolved into solution.

In various embodiments, as described herein, leach 202 receivesprecipitated cobalt 114. Thus, at various times, leach 202 is performedin the presence of gypsum. Leach 202 produces leachate 203, which may beforwarded to filtration 106 to produce filtrate 205. It should belikewise noted that, at various times, leachate 203 comprises gypsum.

Solution extraction 204 may comprise any solution extraction process. Invarious embodiments, solution extraction 204 comprises a liquid-liquidextraction. During solution extraction 204, impurities from the filtrate205 may be loaded selectively into an organic phase in an extractionstage. Impurities may include one or more of copper, zinc, manganese andnickel. In various embodiments, the organic phase comprises anextracting agent, which may also be referred to as an extractant, to aidin transporting the impurities to the organic phase. For example, D2EPHAmay be used as an extracting agent. Cobalt is retained in the aqueousphase and Zn, Mn, and Ca are loaded in the organic phase.

The organic phase from solution extraction 204 may be then subjected toone or more wash stages and/or scrub stages in which the loaded organicphase is contacted with an aqueous phase in order to removeentrained/extracted aqueous solution cobalt bearing solution from theorganic phase. The washed organic phase may then be subject to a solventstripping stage, wherein the impurities are transferred to an aqueousphase. For example, more acidic conditions may shift the equilibriumconditions to cause the impurities to migrate to the aqueous phase.Conditioned solution 118 thus comprises cobalt containing liquid fromsolution extraction 204.

With reference to FIG. 3, metal recovery process 300 is illustrated.Metal recovery process 300 contains certain steps found in metalrecovery process 200, but FIG. 3 illustrates an embodiment comprisingupstream bleed 306. As described above, upstream bleed 306, which islocated after a filtration process, tends to decrease downstreamsolution volumes. Thus, downstream metal recovery processes may act onlower volumes of solution than in previous systems. Accordingly, reagentcost and plant equipment cost tends to be lessened. Moreover, upstreambleed 306 acts as a bleed of impurities such as MgSO₄ and Na₂SO₄ fromthe circuit.

Upstream bleed 306 comprises a portion of filtrate 205. Upstream bleed306 may be used to bleed a portion of filtrate 205 to precipitation andfiltration 112, thus bypassing solution extraction 204. As discussedabove, upstream bleed 306 allows for the reduction of impurities fromthe circuit and for the reduction in process volumes in downstreamprocessing. For example, leachate 203 from leach 202 may be ofrelatively low cobalt concentration. Upstream bleed 306 provides aportion of the liquid phase of leachate 203 to precipitation andfiltration 112, allowing the cobalt to be precipitated and thecobalt-depleted liquid phase with the impurities to be sent to elsewhere(e.g., to tails). Stated another way, upstream bleed 306 acts to reducesolution volumes, in turn reducing the volume of solution that issubject to other metal recovery processes. By reducing volume prior toother processing steps, the volume of solution used in the otherprocessing steps relative to the cobalt contained therein is lower thanin conventional systems. Accordingly, process equipment may be downsizedas the equipment need not be sized to accommodate a large volume of lowcobalt concentration liquor. The reduction in equipment size is also acost savings over conventional systems on a per mass unit of cobaltrecovered basis.

Reagent 304 is added to precipitation and filtration 112 to aid inprecipitation and filtration. In various embodiments, reagent 304comprises lime, but may also comprise limestone slurry.

With reference to FIG. 4, metal recovery process 400 is illustrated.Metal recovery process 400 contains certain steps found in metalrecovery process 300, but FIG. 4 illustrates an embodiment including acobalt precipitation.

As discussed above, cobalt bearing material 102 may be produced inproximity to other metallurgical operations. For example, certain miningoperations recover more than one metal from an ore body. Certain orebodies comprise cobalt and copper, among other metals. Copper may beleached in a primary leaching operation. During the processing of theleachate from such a primary leaching operation, it may be beneficial tobegin cobalt recovery.

Cobalt precipitation 402 may comprise any process by which cobalt isprecipitated out of solution using a precipitant. A precipitant orprecipitating agent, used herein interchangeably, is an agent that, whenadded to a solution, causes at least a portion of a solute toprecipitate. A variety of precipitating agents may be used toprecipitate metal values. Any agent that may precipitate a metal valuefrom an aqueous solution may be used as a precipitating agent.Precipitating agents may include various hydroxides and carbonates. Morespecifically, precipitating agents may include magnesium hydroxide,lime, magnesium oxide (also known in the art as magnesia), ammoniumhydroxide, potassium hydroxide, calcium carbonate, ammonium sulphate,sodium carbonate, magnesium carbonate, potassium, and sodium hydroxide.In an exemplary embodiment, any form of magnesium oxide may be used as aprecipitating agent. For example, forms of magnesium oxide include solidmagnesium oxide, calcined magnesium oxide and slurried, calcinedmagnesium oxide. Cobalt precipitation 402 may comprise multipleprecipitation steps performed in parallel or in series. Product 401 ofcobalt precipitation 402 may comprise cobalt bearing material 102.

With reference to FIG. 5, metal recovery process 500 is illustrated.Metal recovery process 500 contains certain steps found in metalrecovery process 500, but FIG. 5 illustrates an embodiment including adual cobalt precipitation.

The use of one precipitant over another is determined based on a numberof factors. As discussed above, cobalt produced using magnesium oxide isgenerally considered of greater quality than cobalt produced using lime.Generally speaking, industrially produced cobalt hydroxide usingmagnesium is approximately 30%-45% pure, whereas industrially producedcobalt hydroxide using lime is approximately 10%-25% pure. Cobalthydroxide is a commercially marketable product, so the desired return oninvestment may be weighed using the present or predicted market price ofboth materials. Thus, it may be beneficial in operations that produceboth products to adjust the balance of the type and amount of cobalthydroxide that is recovered and the type and amount of cobalt hydroxidethat is marketed directly.

Reagent 502 may comprise magnesium oxide. Reagent 502 may be added tocobalt precipitation I 504 to precipitate cobalt as cobalt hydroxide.Reagent 506 may comprise lime. Reagent 506 may be added to cobaltprecipitation II 508 to precipitate cobalt as cobalt hydroxide. Theprecipitated cobalt hydroxide may be mixed to form cobalt bearingmaterial I.

With reference to FIG. 6, metal recovery process 600 is illustrated.Metal recovery process 600 contains certain steps found in metalrecovery process 500, but FIG. 6 illustrates an embodiment includingelectrowinning to recover cobalt metal.

Cobalt precipitation 602 may comprise any process by which cobalt isprecipitated out of solution using a precipitant. In cobaltprecipitation 602, any form of magnesium oxide may be used as aprecipitating agent. For example, forms of magnesium oxide include solidmagnesium oxide, calcined magnesium oxide and slurried, calcinedmagnesium oxide. Cobalt precipitation 602 may comprise multipleprecipitation steps performed in parallel or in series. Cobaltprecipitation 602 yields precipitated cobalt bearing material 603

Precipitated cobalt bearing material 603 is forwarded to leach 604.Leach 604 is conducted in acid media under the addition of sulfurdioxide gas. Sulfur dioxide addition acts to reduce cobalt III intocobalt II, which is readily dissolved into solution. Leach 604 may beperformed under pressure and at temperatures above 25° C., though invarious embodiments, leach 604 is conducted at atmospheric pressure andat a temperature of about 50° C. Leach 604 yields a leachate that isforwarded to leach residue filtration 608.

Leach residue filtration 608 comprises the thickening and filtering ofsolids from liquids of the leachate. Gypsum, which may be present in theleachate due to, for example, precipitation and filtration 610, isbelieved to act as a filtering aid in leach residue filtration 608.Leach residue filtration 608 produces solids 630. Solids 630 may beforwarded to, for example, a primary leaching process. In that regard,residual metals in solids 630, such as copper and cobalt, may berecovered. In various embodiments, solids 630 are sent to residue and/orneutralization 628. Neutralization 628 may comprise any suitable wastemanagement or neutralization process. For example, lime may be added inneutralization 628 to regulate the pH of effluent prior to furtherprocessing.

The liquid portion of leach residue filtration 608 may be forwarded toZn/MTn/Ca SX 606. Zn/Mn/Ca SX 606 comprises a solution extractionprocess that removes, among other tbigs, Zn, Mn, and Ca from the liquidportion of residue filtration 608. As discussed above, the aqueousliquid portion of leach residue filtration 608 may be contacted with anorganic solution and an extractant. Zn/Mn/Ca SX 606 uses D2EHPA as anextractant. After impurities are brought in the organic phase, theorganic phase may be washed with water, though in various embodimentsthe organic phase is not washed. The organic phase may be scrubbed withdilute sulfuric acid to strip any cobalt that was extracted from theaqueous phase. After scrubbing, the dilute sulfuric acid, which nowcontains cobalt scrubbed from the organic phase, may be sent back toprecipitation and filtration 112 via scrubbed cobalt solution 270. Theorganic phase may be scrubbed with dilute sulfuric acid to strip anycobalt extracted from the aqueous phase. The scrubbed cobalt may then besent back to precipitation and filtration 112. The organic phase may bestripped with an additional aqueous phase to bring impurities to theaqueous phase. The additional aqueous phase may be suitably treated.Acid for stripping the organic phase may be generated from otherprocesses. The aqueous phase Zn/Mn/Ca SX 606 produces may be referred toas extracted cobalt bearing solution 609.

Extracted cobalt bearing solution 609 is then subjected to organicpolishing 614. Organic polishing 614 comprises a filtration of extractedcobalt bearing solution 609 in a carbon column. A carbon column maycomprise any suitable carbon media, such as, for example, activatedcharcoal, powdered activated carbon or granulated activated carbon.Carbon media may adsorb various impurities from extracted cobalt bearingsolution 609. For example, carbon media may adsorb organic compoundsfrom extracted cobalt bearing solution 609. Carbon media is suited foradsorption due to its high surface area, among other properties. In thatregard, other media may be used in organic polishing 614 that aresuitable for adsorbing or absorbing organic compounds. Carbon media mayperiodically be regenerated or replaced to maintain appropriateadsorbing performance. Organic polishing 614 produces polished cobaltbearing solution 611.

Polished cobalt bearing solution 611 may be forwarded to copper ionexchange (Cu IX) 616. Copper may be present at relatively lowconcentrations in polished cobalt bearing solution 611. Copper presentin polished cobalt bearing solution 611 may exist as copper I and/orcopper II. Cu IX 616 may be used to remove copper. Copper removed by CuIX 616 may be in either metal or ionic form. Ion exchange may beaccomplished in any suitable manner. For example, polished cobaltbearing solution 611 may be contacted with a surface or membranecontaining ions. A surface or membrane in an ion exchange step may becomprised of a synthetic resin, a polymer, or any other suitablematerial. In various embodiments, for example, LEWATIT MONOPLUS TP207resin, made by Lanxess of Birmingham, N.J. USA, is used. In furtherembodiments, PUROLITE S950 resin, made by Purolite, Inc. of 150 MonumentRoad, Bala Cynwyd, Pa. 19004, USA is used. Copper from cobalt bearingsolution 609 may be exchanged with ions present on the surface ormembrane, leaving copper present on the surface or membrane. Themembrane or surface may be washed periodically to remove the adheredcopper and increase efficacy of the ion exchange step. During suchperiodic washing, acid or other media may be contacted with the membraneor surface to remove the deposited copper ions. The acid or other mediamay be recycled into a primary leaching process to recover the copperions washed off the membrane or surface. Cu IX 616 produces exchangedcobalt bearing solution 613. Copper removal could also be done with asuitable organic extractant using liquid liquid extraction, although invarious embodiments, solvent extraction is not used for removing copper.

Exchanged cobalt bearing solution 613 is subjected to organic polishing618. Organic polishing 618 may be conducted in the same or similarmanner as organic polishing 614. For example, exchanged cobalt bearingsolution 613 may be contacted with a carton column to further removeimpurities, such as organic compounds. Organic polishing 618 producespolished cobalt bearing solution 615.

Cobalt bearing solution 615 may be subjected to nickel ion exchange (NiIX) 620. NiIX 620 may be accomplished in any suitable manner. Forexample, cobalt bearing solution 615 may be contacted with a surface ormembrane containing ions. A surface or membrane in an ion exchange stepmay be comprised of a synthetic resin, a polymer, or any other suitablematerial. In various embodiments, for example, DOWEX M4195 resin isused. DOWEX M4195 is made by the Dow Chemical Company, Dow WaterSolutions, Customer Information Center, P.O. Box 1206, Midland, Mich.48642-1206. In further embodiments, for example, DOWEX XUS43605 resin isused. DOWEX XUS43605 is made by the Dow Chemical Company, Dow WaterSolutions, Customer Information Center, P.O. Box 1206, Midland, Mich.48642-1206. Nickel from cobalt bearing solution 615 may be exchangedwith ions present on the surface or membrane, leaving nickel present onthe surface or membrane. In various embodiments, a portion of the cobaltin polished cobalt bearing solution 615 may also become bound to thesurface or membrane. NiIX 620 produces purified cobalt bearing solution617.

The membrane or surface may be washed periodically to remove the adheredcobalt and increase efficacy of the ion exchange step. For example, CoElution 624 comprises a regeneration or purging of the membrane orsurface of NiIX 620 to remove cobalt that may have adhered to themembrane or surface. In that regard, Co Elution 624 may comprisecontacting an elution medium, such as an acid medium, with the membraneor surface. The elution medium may be conducted to leach 604 to improvecobalt recovery.

The membrane or surface may be washed periodically to remove the adherednickel and increase efficacy of the ion exchange step. Ni Elution 626comprises a regeneration or purging of the membrane or surface of NiIX620 to remove nickel that may have adhered to the membrane or surface.In that regard, Ni Elution 626 may comprise contacting an elutionmedium, such as an acid medium, with the membrane or surface. Theelution medium may be conducted to tails.

Purified cobalt bearing solution 617 may be forwarded to electrowinningcell 622. Electrowinning cell 622 yields a cobalt metal cathode product.As those skilled in the art are aware, a variety of methods andapparatus are available for the electrowinning of cobalt and other metalvalues, any of which may be suitable for use in accordance with thepresent invention, provided the requisite process parameters for thechosen method or apparatus are satisfied.

In various embodiments, electrowinning may be performed inelectrowinning cell 622 such that the anodes and cathodes are housed inseparate compartments. For example, electrowinning cell 622 may comprisea cathode compartment and an anode compartment. Compartments may beformed by the placement of a bag or other barrier, whether permeable orsemi-permeable, around or partially around one or more of the anodes andcathodes. For example, a bag may be placed around all or a portion of ananode. Cobalt metal may evolve at the cathode. Manganese, among othersspecies, may evolve at the anode.

In various embodiments, electrowinning may be performed inelectrowinning cell 622 such that the anodes and cathodes are notseparated into compartments. In such embodiments, the anodes andcathodes are placed in the same media without a barrier and electricalcurrent is applied. For example, electrowinning cell 622 may comprise acathode compartment and an anode compartment. Metal values, such ascobalt, may evolve at the cathode. Manganese, among others species, mayevolve at the anode.

It is believed that the disclosure set forth above encompasses at leastone distinct invention with independent utility. While the invention hasbeen disclosed in the exemplary forms, the specific embodiments thereofas disclosed and illustrated herein are not to be considered in alimiting sense as numerous variations are possible. Equivalent changes,modifications and variations of various embodiments, materials,compositions and methods may be made within the scope of the presentinvention, with substantially similar results. The subject matter of theinventions includes all novel and non-obvious combinations and subcombinations of the various elements, features, functions and/orproperties disclosed herein.

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any element orcombination of elements that may cause any benefit, advantage, orsolution to occur or become more pronounced are not to be construed ascritical, required, or essential features or elements of any or all theclaims or the invention. Many changes and modifications within the scopeof the instant invention may be made without departing from the spiritthereof, and the invention includes all such modifications.Corresponding structures, materials, acts, and equivalents of allelements in the claims below are intended to include any structure,material, or acts for performing the functions in combination with otherclaim elements as specifically claimed. The scope of the inventionshould be determined by the appended claims and their legal equivalents,rather than by the examples given above.

1. A method comprising: leaching a cobalt bearing material to form aslurry; filtering the slurry to yield solids and a cobalt bearing liquidphase; performing a solution extraction of the cobalt bearing liquidphase to yield a purified cobalt bearing liquid phase; precipitatingcobalt gypsum by adding lime to a first portion of the purified cobaltbearing liquid phase; and recycling the cobalt gypsum to the leaching.2. The method of claim 1, further comprising forwarding the solids to asecond leaching operation.
 3. The method of claim 1, further comprisingbleeding a portion of the cobalt bearing liquid phase to theprecipitating step.
 4. The method of claim 1, further comprisingforwarding the solids to tails.
 5. The method of claim 1, wherein thecobalt bearing material comprises cobalt hydroxide.
 6. The method ofclaim 5, wherein the cobalt hydroxide is formed by precipitating cobaltII with magnesia.
 7. The method of claim 6, wherein the cobalt hydroxideis formed by precipitating cobalt II with lime.
 8. The method of claim1, further comprising subjecting a second portion of the purified cobaltbearing liquid phase to an additional conditioning step to yield aconditioned cobalt bearing liquid.
 9. The method of claim 8, furthercomprising bleeding a portion of the conditioned cobalt bearing liquidto the precipitating step.
 10. The method of claim 2, wherein the secondleaching operation is a copper leaching operation.
 11. The method ofclaim 8, further comprising electrowinning cobalt metal from a firstportion of the conditioned cobalt bearing liquid.
 12. The method ofclaim 11, wherein the electrowinning comprises a bagged anode process.13. The method of claim 1, wherein the electrowinning comprises a freeanode process.
 14. The method of claim 11, wherein the electrowinningcomprises depositing cobalt metal rounds on a masked cathode.
 15. Themethod of claim 11, further comprising performing a cobalt selectivesolution extraction on a second portion of the conditioned cobaltbearing liquid to yield a refined cobalt containing liquid.
 16. Themethod of claim 15, further comprising precipitating cobalt salt byadding a precipitating agent to the refined cobalt containing liquid.17. The method of claim 16, wherein the precipitating agent comprisessodium carbonate.
 18. The method of claim 8, wherein the additionalconditioning step comprises eluting through a carbon column.
 19. Themethod of claim 8, wherein the additional conditioning step comprisescopper ion exchange.
 20. The method of claim 8, wherein the additionalconditioning step comprises nickel ion exchange.